The Consequences of Small Mammal Censuses by Method of Irreversible Removal

Abstract

Experiments were performed to estimate the effect of removal trapping with Gero trap lines on resident population density and dispersal rate of Clethrionomys voles and Sorex shrews. Parameters of animal density and dispersal were calculated based on the results of live-trap censuses taken before and immediately after the removal trapping. Resident population density in the latter case was accounted for not only by animals that escaped removal but also by those that moved in from surrounding areas during the next few days. Local reduction of animal numbers resulted in increased dispersal. Parameters of dispersal obtained by the method of long-term removal may be overestimated.